Tubular reaction apparatus



Oct. 12', 1926.

T. GRIS'WOLD. JR

TUBULAR REACTION APPARATUS original Filed June 19I i525 2 Sheets-Sheet 1 www@ Oct. 12 1926.

T. GRISWOLD, JR

TUBULAR REACTION APPARATUS sheets-sheet 2 origina; Filed June 19. 1925 INI/ENTOR. momdsfiswal .721

v A TTORNE YS u`NlTa-nfSTATES PATENT OFFICE.`

zrHoMAs emswonn-n, or MIDLAND, MICHIGAN, AssIGNoR To THE Dow CHEMICAL COMPANY, or -'-MI;DL AND, MICHIGAN, -A

CORPORATION MICHIGAN.

#1" l TUBULAR REACTION APPARATUS.

Application ill-ed June 19, 1925, Serial No. 38,290. RenewedpAugust 26, 1926.

The present improvements relate more particularly toa form of tubular autoclave suitable for 'carryingf'on chemical reactions wherein the mixtureof reacting ingredients 5 requires to be maintained at a high temperature and under high pressure for a considerable length of time in order that the reaction may be carried to completion. As an illustration of 'a process' of the type in questlon,

reference may be had 'to the manufacture of phenols and amines from halogenated.

benzene hydrocarbons. Thus, specifically, it is known that an alkali metal phenate may be made by reacting betvveenpmono-chlorbenzene and caustic alkali in aqueous solution at temperatures between 2500 and, 400- C., provided a pressureV greater than the vap'oi"tension of thereacting substances 1s l maintained. Thev phenate thus produced,

may then be treated with an acid to liberate phenol, CGI-15CH, and the latter separated from the solution in the usual way. n

There are obvious advantages iny conducting a process of this sort in a tubular autof clave through which such reacting substances may be .passed continuously, fresh material being supplied at the one end and the product of the reaction being drawn off at a corresponding rate at the other end. Aside, however, from serious constructional difficulties, dueto the high temperatures and pressures involved, a tubular system suitable for a process of the kindV just referred to requires to be of a very considerable length 85 in order to have the necessary capacity and allow for the necessary time interval if the reaction is to becarried to even approximate completion and of course if this isv not done, the process is uneconomical. There 470 is also presented a problem of control both as to rate of 'flow of the reacting substancesvand the pressure within thesystem, vsuch pressure beingwaried not'only by the rate of supply, which can of course be regulated' more or less nicely, butl also by variations in temprature, which,` latter necessarily tends to fluctuate somewhat.

The object of the present invention, accordingly, is to provide an apparatus of the type in question in which a tubular system of adequate length may be utilized and yet vpermit vof-an extremely close and auto-4 matic regulationof the pressure therein. A further object 1ste utlllze 1n an economlcal 'fashion the heat required to bring the re- 1acting substances to the proper temperature and to maintain such temperature through- 'out the system. Still another 'object is to -provide for the automatic discharge of the l products of the reaction from the system.

To the accomplishment of the foregoing.

and related ends, the invention, then, consists of the means hereinafter full scribed and particularly pointed out 1n the claims, the annexed drawings and the following description setting forth in detail certain mechanism embodying the invention,

however,

such disclosed means constituting, but one of various mechanical which the used.

In said annexed. drawings forms 1n prmciple 'of the invention vmay be Fig. 1 is a'diagrammatic representation of tion; and Fig. .4 is a sectional -view of a detail of one of the control devices utilized in connection with the system.

y Referring-to the general layout of a typical plant as illustrated in F ig.y 1, the reacting material, as for example mono-I chloro-benzene and caustic alkali solution, are supplied either continuously or at intervals and in the proper proportion from charging tanks l, 2, respectively,to a supply tank 3 equipped with a stirrerf 4. -Froml such last mentioned tank the liquid mixture is withdrawn through a strainer 5 and forced by means of `a .triplex pump 6 into the supply line 7 proper of ythe autoclave.'

Leading back from such supply line to tank 3 is a return line 8 with a safety relief valve 9 interposed therein, and at a suitable point in such supply'line a pressurel'gauge l0 is attached.

The first unit of the autoclave is'a heater a by-pass Hue 28,

lat

ysufficient space being left between such coils thereabout ot comso as to allow i'free play bustion gases where the heat is applied through this medium. rlhe second unit oit the autoclave is a reaction unit and consists of, a plurality of coils similar to those used in the heater unitbut preferably more closely spaced together. rlhe pipe in the individual coils, moreover, in such reaction unit will be as closely wound as possible. Freely connected in turn with the reaction unit is a cooling coil 15, the detail construction of which does not require description, and from the latter leads the discharge line 16 of the system, such discharge line being controlled ,by a suitable valve 17 and a tank 18 being provided to receive the discharge trom said line.

`Valve 17 is operatively connected through suitable means, such as those presently to be described, with a fluid pressure actuated control unit 19 that is connected by means oi' `a branch 20 with discharge line 16 at a point between said valve 17 and the cooling coil 15. Said unit 19 is adjustable so as to open valve 17 more and more widely as pressure is built up in the autoclave and to close said valve more and more as such pressure falls.

As indicated, the heating unit` 11 is most conveniently raised to the temperature at which thereaction between the ingredients supplied to,k the autoclave will react by means ol gases ol' combustion, one illustrative arrangement Abeing shown in Fig. 2 where such coil is so located with respect to combustion chamber 25 as to cause the gases of kcombustron to pass through the unit in a direction opposite to that in which the liqnid mixture passes therethrough, this being advantageous for eilicient heat transfer. ln the specific embodiment-shown in Fig. 2, the reaction unit 13 is located in a second chamber 26 adjacent the lportion of the combustion chamber in which the heating unit is thus placed and the stack 27 may be optionally connected with such combustion chamber either through said chamber 26 or through suitable dampers or valves ath which such gases travel. ln operatln t is form of the apparatus, the gases o' combustion are initially byassed to raise the temperature of thel heating coil and then during the further operation of the apparatus, the temperature of the reaction coil is maintained with waste heat from the combustion chamber.

ln the alternative form of construction shown 1n Fig. 3, the locationand arrangement ot the heating unit with respect to combustion chamber 25 remains unchanged, but the Hue 29 is here directly connected with such chamber and the reaction coil 13 controlling the tween said device recare@ Vis located in a chamber 30 entirely disconstill adjacent to said A packing 31 of heat closely surnected from although combustion chamber. insulating material, furthermore,

rounds said reaction coil so as to prevent,

as far as possible, radiation of heat therefrom.

` rlhe pressure controlled device 19, illustrated in Fig. 4, for operating valve 17 takes the form of a weighted plunger 35 that is vertically reciprocable in a liquid tight chamber 36 and the connections beand the valve take the form of a sheave 37, mounted on the stem of the valve, and a cord or chain 38 that passes around said sheave, one end of the cord being attached to the upper weighted end 39 of plunger 35 by means of a weight 4() to which such cord end is attached, while a second smaller weight 41 is attached to the free end of the cord so as to hold the latter in necessary rictional contact with sheave 37. rl`he weight 39 on the end of the plunger is of such a. character that the load on the plunger may be varied so that it will be litted upon a predetermined pressure being built up within chamber 36. Such chamber being in free communication with the series oit coils 11, 13 and 15, the pressure therein will of course correspond with the pressure in thelatter and such pressure in turn will be indicated by the gauge'lO.

lt will be understood that various other forms 'of Huid pressure actuated regulating devices may be employed to operate the discharge valve 17, suoli' for example as a Bourdon gauge or similar instrumentality, either connected directly with the valve or by means ot a relay.

rlhe operation of the system as a whole will be readily understood from the toregoing description of the construction and operation of its several component parts. rllhe liquid reaction mixture received through line 7 first passes through coil 11 where it is quickly heated to the optimum temperature, e. g. 250 to 400 C., inthe case of the particular ingredients referred to above, the particular Atemperature that will be best for such reaction depending on various considerations that do not form a part of the present invention. By the time such liquid mixture hasl been brought to the desired temperature, it passes over into the reaction coil which is of such length that at the given rate of flow a sullicient body of the mixture will remain therein to permit substantial completion of the reaction, providing the necessary temperature is maintained. each of the two forms of construction illustrated in Figs. 2 and 3, respectively, it will be noted that the direct application ot heat from the furnace chamber is found unnecessary and in fact struction not even the waste heat from such llltl llt? llli

in the second cony combustion chamber is utilized; on the contrary, it has been found satisfactory simply to insulate the reaction coil so as to prevent radiation as far as possible of heat therefrom, with the y,result that the liquid mixture continues on itsl course through said coil `,15 ically taken` care `of by the pressure controlled device l9-which operates the valve 17 Y so as to allowr the liquid mixture to ow through line 16 at the same rate as it is supplied through pum 6 to line 7.

Other modes of app ying the principle of my invention may be employed instead of the one explained, change being made as regards the mechanism herein disclosed, provided` the 'means stated by any of the following claims or the equivalent of such stated means be employed. I

I therefore particularly point out and disftinctlyclaim as my invention '1. The combination of two liquid-containing receptacles connected in series, the secon'd of said receptacles comprising a plurality of coils, means adapted to cause a low of liquid through said receptacles under pressure, means for heating said first receptacle, and heat-insulating means surrounding the second receptacle. i

2. The combination of two liquid-containing receptacles connected in series, the second of said receptacles comprising a lu- 40 rality of coils, means adapted tocause a ow of liquid through said receptacles under pressure, means for heating said fl t receptacle,

heat-insulating means surrounxing the second lreceptacle, and means adapted automatically to regulate the pressure of the liquid in said receptacles. 3. The combination of three liquid-containing receptacles connected inseries, the second of said receptacles comprising a plurality of coils, means for supplying liquid to the rst and means for withdrawing liquid from'the last' of said rece tacles, means' for heating said first receptac e, and heat-insulating means surrounding the second recep-` tacle, the third receptacle being exposed to a cooling medium. 4. The combination of three liquid-containing receptaclesconnected in series, the second of said receptacles comprising a pluto the first andmeans for withdrawing liquid from the last of said receptacles, means for heating said first receptacle, heat-insulating j means surrounding the second receptacle, the third receptacle-being exposed to a cooling rality of coils, means for supplying liquid4 medium, .and means associated with said liquid withdrawing means, adapted automatically to regulate the pressure' of the n liquid in said receptacles.

5. The combination of two liquid-receptacles connected in series, each said receptacle comprising an extended tubular passageway,

means for heating the first tubular passage-l way, and means for preventing substantial heat-loss from the second tubular passageway. l

6. The combination of a heating coil," af

furnace associated therewith, a heat-insulated reaction coil connected with said heating coil, and means for supplying liquid to said heating coil and for withdrawing liquid from said reaction coil.

`7. The combination of a heating coil, a furnace associated therewith, a heat-insulated reaction coil connected with said heating coil, means for supplying liquid to said heating coiland for withdrawing liquid from said reaction coil, and means associated with said ,liquid withdrawing means adapted automatically to regulate the pressure of the liquid in said coils.

8. ,The combination of a heating coil, a

furnace associated therewith, a heat-insulated reaction coil connected with said heating coil, a cooling coilconnected in turn with 'said reaction coil, and `means for supplying liquid to said heating coil and for withdrawing liquid from said cooling coil.

9. The combination of a heating coil, afurnace associated therewith, a heat-insulated reaction coil` connected with said heating coil, a cooling coil connected in turn with said reaction coil, means for supplying liquid to said heating coil and for withdrawing liquid from said cooling coil, and means adapted automatically to regulate the pressure of the liquid in said coils. f 10. In a high-pressure, high-temperature tubular reaction-ap aratus, the combination of a furnace, a coil or heating liquid located in said furnace, a heat-insulated reaction coil connected with said heating coil, a cooling coil connected in turn with said reaction coil, means for supplying liquid under pressure to said heating coll, means for with-l drawing liquid 'from said cooling coil, and

means associated with said liquid withdrawing means adapted automatically to regulate the pressure o the liquid in said coils.

11. In a high-pressure, high-tem erature tubular reaction-apparatus, the com ination of a furnace, a coil for heating liquid located 'i in said furnace, a heat-insulated reaction coil connected with said heating coil, a coolin coil connected in turnwith said reaction coi means for supplying liquid under pressure to said heating coil, a valve controlling the withdrawal of liquid from said cooling coil, and a device res nsive to the pressure `in said coils adap tooperate said valve.

y12. iin a high-pinssnm, nigh-Tunning)@mainline tubular reaction-a params, the 'combination of si furnace, a coi 17501* heating liquid iocwtd in said furnace., ai heat-insulated reaction co;

5 connecte with said heating coii, a cooling coil connected in turn with said reaction coil, means foi' supplying liquid under preswww@ sur@ to smid heating mii, a Valve connmiiing th@ withdraws/'ni liquidi from said cooling coii, nndi mi ndjustnb@ dni/ice nesponsive t@ the pnnnnn-in said coils adapted t@ operai@ said vnlwm Sig'nnni by ine, iths 15th day of June, 1925U THS. GRSi/VLD, JR. 

